Offshore oil and natural gas in the Gulf of Mexico represents a major source of fossil fuels within the United States. The western and central gulf, including offshore areas proximate Texas, Louisiana, Mississippi, and Alabama constitutes one of the richest petroleum producing areas in this country. In fact, statistics show that federal leases to conduct off-shore drilling in the area have resulted in producing over 25 percent of the nation's oil and some 14 percent of the nation's natural gas needs.
With advances in oil drilling and production technologies in recent years, oil companies have extended drilling farther from shore and into deeper waters. Oil drilling from depths greater than 1,000 feet began in 1979. Currently, some 72 percent of oil production in the Gulf of Mexico comes from drilling in waters greater than 1,000 feet deep. Some sixty-five oil discoveries have been made in waters greater than 5,000 feet. In fact, oil has been discovered in waters as deep as 9,875 feet. These deep water drilling activities produce some 400 million barrels of oil each year, with projections that by 2013 oil production for the gulf will near 700 million barrels yearly.
Offshore oil drilling and prospecting in the Gulf of Mexico is conducted by large semi-submersible mobile offshore drilling units (MODUs). MODUs are massive floating dynamically positioned drilling rigs which can operate in waters up to 8,000 feet deep and drill up to 30,000 feet. Most MODUs are owned and operated by large drilling companies and are leased by large petroleum manufacturers and refiners. Such MODUs are capable of moving about the Gulf of Mexico to drill into deep waters to prospect for oil, and then prepare the area for later pumping and recovery of the oil by other offshore rigs.
One of the glaring issues relating use of MODUs employed to drill in the Gulf of Mexico is the inability to access drilling areas created via the process. As the drilled areas often are located well over a mile below sea level, there is no ability for manned submersibles (let alone divers) to access a drilled site to correct any accident—such as a leaking drill site. Instead, robotic submersibles (and/or lowering of ‘top hat’ containment housings via barges/tankers positioned above the drill site) must be used to help fix leaking pipes tied to leaking drill sites.
The limits of robotic submersibles and rudimentary containment housings has been realized with the Apr. 20, 2010 Deepwater Horizon MODU explosion and resulting oil spill. As has been well documented by the media, on Apr. 20, 2010, methane gas from a well being created by the Deepwater Horizon shot up and out of the drill column marine riser, ignited and exploded. The result was a fire which engulfed the platform, killing several workers, and ultimately caused the MODU to sink the morning of Apr. 22, 2010. Several days later, it was confirmed that the wellhead, positioned on the ocean floor, was indeed leaking oil into the Gulf of Mexico.
While there exist several devices known to those of ordinary skill in the art to cap and/or seal such leaking wellheads (located deep within the sea floor), the efforts of British Petroleum relating to the Deepwater Horizon disaster have shown the limitations of the current state of the art. For example, the current technology for curing a leaking wellhead has included a containment dome, known as a ‘top hat’ which is lowered to the sea bed and deployed over the oil leak. Both the weight of the ‘top hat’ and the dimension would allow oil to be recovered and pumped to tankers above the accident area without risk of further leaking into the Gulf of Mexico. However, when there is a high level of gas and petroleum flow, as exhibited with the Deepwater Horizon disaster, such ‘top hat’ can have limited if any successful impact on sealing the area.
Accordingly, there is a need for a robust and cost effective device to reduce flow-thru of escaping petroleum (and natural gas) caused by drilling accidents in the deep sea. Such device should allow quick and effective reduction of an oil leak in areas in which manned submersibles (as well as divers) are unable to repair.